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Beyond thiols, beyond gold: Novel NHC-stabilized nanoclusters in catalysis

超越硫醇，超越金：催化中新型 NHC 稳定纳米团簇

基本信息

批准号：
21H01949
负责人：
CRUDDEN Cathleen
金额：
$ 11.23万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2021
资助国家：
日本
起止时间：
2021-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-21H01949/
关键词：
nanocluster gold N-heterocyclic carbene catalysis chirality chiral C-H oxidation

项目摘要

In FY 2022, we successfully synthesized gold nanoclusters stabilized by N-heterocyclic carbene (NHC) ligands in collaboration with the Tsukuda and Hakkinen group. We demonstrated that the use of chiral, BIANP-inspired NHCs to prepare chiral Au10 nanoclusters with a unique elongated central Au10 core. ESI-MS and single-crystal X-ray crystallography confirmed the molecular formula to be [Au10(bisNHC)4Br2]2+. The chiral Au10 nanocluster adopts a linear edge-shared tetrahedral geometry with a prolate shape. The UV-vis spectrum this cluster in CH2Cl2 displayed four prominent absorption bands at 291, 325, and 546 nm, which is a significant departure from the spectra of bis-NHC dinuclear Au(I) complexes. CD spectra demonstrate chirality transfer from the chiral bisNHC ligand to the inner Au10 nanocluster core. The reaction monitoring by ESI-MS and UV-vis spectroscopy indicated the formation of [Au9(bisNHC)4Br]2+ as a key intermediate.In addition, we achieved the synthesis of a toroidal Au10 cluster stabilized by NHC bearing bulky 2,4,6-trimethylbenzyl units. The [Au10(NHC)6Br3]Br cluster readily undergoes conversion to form a biicosahedral Au25 cluster, while the corresponding Cl cluster showed no conversion. This facyt may be explained both by the steric environment imposed by the bulky mesityl-substituted NHC ligand, as well as steric and electronic factors introduced by the smaller chloride ligands.

于2022财政年度，我们与Tsukuda及Hakkinen小组合作，成功合成由N-杂环卡宾（NHC）配体稳定的金纳米团簇。我们证明了使用手性，BIANP启发的NHC来制备具有独特的细长中心Au 10核心的手性Au 10纳米团簇。ESI-MS和单晶X射线晶体学证实分子式为[Au 10（bisNHC）4 Br 2]2+。手性Au 10纳米团簇采用线性共边四面体几何形状，具有扁长的形状。紫外-可见光谱表明该簇在291、325和546 nm处有4个明显的吸收带，这与bis-NHC双核Au（I）配合物的光谱有很大的不同。CD光谱表明手性转移从手性bisNHC配体的内部Au 10纳米团簇核心。通过ESI-MS和UV-vis光谱对反应过程进行了监测，结果表明反应中形成了关键中间体[Au 9（bisNHC）4 Br]2+，此外，我们还合成了一个由NHC稳定的带有2，4，6-三甲基苄基结构单元的环状Au 10簇合物。[Au 10（NHC）6 Br 3]Br团簇容易发生转化形成双二十面体Au 25团簇，而相应的Cl团簇没有发生转化。这facyt可以解释由庞大的mesityl-substituted NHC配体施加的空间环境，以及由较小的氯配体引入的空间和电子因素。